There might be a number of reasons why 80% of women are wearing the wrong-sized bra: ignorance, embarrassment or basic laziness, but the effect of your ill-fitting lingerie is almost always the same - it’s bad for your health.

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“It’s worrying to think that around threequarters of women in the UK are still wearing the wrong bra size,” says Elise Recour, managing director at Gossard.

“We’ve seen a shift in the media in recent years thanks to high-profile campaigns surrounding breast health but many women are still unaware of the connection between general breast health and wellbeing and wearing the right sized bra.”

Here’s what the wrong-sized bra could be doing to you.

1. Sagging and chaffing

“If your bra is too tight it can cause skin damage and reduce the blood circulation, as well as feeling uncomfortable,” says Recour.

“This is not just applicable to larger cup sizes, it is just as important to wear the right sized bra for smaller breasts as a wrongly fitting one can lead to sagging breasts and chaffing.”

Suzanne Pentalnd, an expert bra fitter for Freya adds: “Your bra should not move throughout the day. The band should be firm enough to sit in place but if it’s too big, your bra will move and this causes rubbing on the skin, which can cause irritation.”

2. Headaches

It doesn’t stop at skin-deep either.

“A poorly fitting bra offers a lack of support to the cleavage, which then means the neck and upper back muscles are having to work harder to support the weight of the breasts,” explains physio and osteopath Tim Allardyce from Surrey Physio.

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“As soon as the neck muscles become overworked, you are far more likely to get headaches (known as cervicogenic headaches, or neck in origin headaches).”

3. Sore neck

“This is not an issue with smaller breasts,” Allardyce adds, “but with larger breasts, it can be quite a strain on the neck muscles. A properly fitted bra will offer support by taking some of the weight from the breasts and distributing it away from the neck.”

4. Stiff back

It continues down the body too. “A bra that is too tight restricts movement in the upper back, causing stiffness in the spine and restriction. Spines are designed to move, to bend, to rotate, but experts believe that the section where the bra strap is often has a localised stiffness at the spine (the two vertebra around the bra strap tend to be quite stiff). This causes backache which can then develop into back pain.”

5. Shortness of breath

You won’t actually feel short of breath if your bra is too tight, but the quality of your breathing will fall.

“There is the opinion that bras that are too tight can restrict the movement of the ribs,” explains Allardyce.

“Although this won’t cause any noticeable change in breathing rate or shortness of breath, it does impact on the breathing mechanics and makes it more likely you will be a shallow rib breather. This can affect the concentration of oxygen and carbon dioxide in the blood, so deep breathing is always more preferable.

“It also means you are more likely to recruit the neck muscles for breathing (known as secondary inspiratory muscles) and this shortens the neck muscles and can lead to neck pain.”

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6. General tenderness

If you’ve ever tried to do exercise wearing a normal bra or no bra at all, you will know the pain that ensues – big boobs or not. The reason for this is that “breasts move a massive 8cm during even moderate exercise,” says Recour. If that movement isn’t supported, it’s no wonder you feel in pain afterwards.

“A properly fitted sports bra will reduce that movement by up to 83% (compared to less than 35% provided by a regular bra).
“It’s essential to get measured separately for your sports bra – a sports bra is a structured piece of technical equipment designed specifically for the purpose of supporting your breasts but it can only do this to the optimum if it is properly fitted.”

For more information, see Gossard’s online measuring guide.